The acquisition of data on objects with volume which permits their subsequent reconstruction with computerised means is an active line of research due to its interest and multiple applications.
The acquisition and reconstruction of three dimensional images is a task which has been widely addressed in the field of “computer viewing”. The methodologies employed are diverse, such as, for example, those based on structured light or multi-vista stereoscopy, which included those known as “Shape from Silohuettes” or “Shape from Voxel Occupancy” and those based on “Shape from Photo-Consistency”. The first have as a limit the reconstruction of “visual hull” of the objects analysed and the second can go further, however, they depend on the existence of characteristic points discernible in the objects.
With respect to the application for which the invention is designed, the control and inspection of objects in order to verify their three dimensional form and their volumetric measures, as well as the image of their surface, is an important area within the scope of “Industrial Vision”.
Almost all the existing applications and solutions are based on reconstruction of part of the object to be inspected and not the whole, as this is usually rested on a conveyor belt which only permits one face thereof to be viewed. In this case, the movement of the object in front of a camera and the use of structured light (typically a laser light line) permit a longitudinal sweep of the same, thus obtaining a series of height profiles which will provide reconstruction of the object. We could call this reconstruction “20 and ½”, in order to distinguish it from the full 3D reconstruction of the whole object which is provided in this invention.